Budget limits? Pieces? Lighting? For reference, the photo I posted up there is perfectly playable, and has about 1500 objects and a lightmap at 170% or more, so if you could explain why budget is the concern in your case, that would be super helpful. Or, if you could show us what the “turns and crossroads” in the hallways are like, that would be cool too. Edit: I gather from the ‘layout’ screens you posted there is a small amount of vertical movement in the hallways, will this have any bearing on outside gameplay, or is it fully contained in the hallways?